Changes in pulmonary function resulting from inhalation of airborne pollutants are being estimated using a whole body pressure plethysmograph constructed for use with small animals. Both acute and chronic exposure to oxidants, singly and in combination with other compounds, result in functional changes. Changes in pulmonary mechanics (e.g. resistance, compliance), spirometry (e.g., lung volumes, frequency of breathing), heart rate, and pulmonary morphology will be estimated.